In case you aren't able to pay through Kickstarter, Obsidian Entertainment is now accepting Paypal donations for Project Eternity (you can find the Paypal donation column on the right). As far as I can see, there is no Paypal donation counter, so it's difficult to know how much Paypal will add up to Kickstarter by the end of the campaign, but going by historical precedents like Wasteland 2, it should be orders of magnitude less than the Kickstarter sum.

There is also no mention in the FAQ of the differences with the Kickstarter system, but I'm assuming that you'll have to pay upfront, rather than waiting at the end of the drive like with the Kickstarter.